Hairspring overcoil raising tool



July 18, 1950 wyo. BENNETT, JR

HAIRSPRING OVERCOIL RAISING TOOL Filed Oct. 16, 1944 m www mm Patented July 18, 1950 HAIRSPRING OVERCOIL RAISING TOOL William Ogle Bennett, Jr., Lancaster Township, Lancaster County, Pa., assigner to Hamilton Watch Company, Lancaster, Pa.

Application October 16, 1944, Serial'No. 558.815v

4 Claims.

1 'Ihis invention relates to a tool for raising the :overcoil on hairsprings of the ner type watches. v'l'n order to assure the isochronal quality of a :watch it is necessary that the hairspring be made to expand and contract equally in all directions.

It has been found that proper overcoiling of the hairspring allows this expansion and contraction to be more nearly concentric than if the outer end f the hairspring is secured to the cock in the same plane, and consequently the isochronism is better. This makes it necessary to raise the outermost coil of the hairspring above the plane of the main section of the hairspring and to curve said raised coil inward in a certain predetermined curve. To maintain uniformity in hairsprings it is highly desirable that the raising be done by means of a machine or tool which eliminates any human element. The tool forming the subject of this invention is utilized for raising the last coil of the hairspring above the plane of the remainder of the spring.

The object of the present invention is to provide a tool which raises the outermost coil of the hairspring to Ia position above the plane of the main body of the spring.

A further object of the present invention is to provide a tool by means of which the outermost `of the h'airspring may be regulated so that the overcoil may be raised a predetermined amount.

It is a still further object of the present invention to provide means for supporting a hairspring while on the balance and for raising the overcoil while the hairspring remains attached to the balance.

It is a still further object of the present invention to provide means by which the outermost coil of the hairspring is rmly held and the raisn ving accomplished in a single operation.

It is a still further object to raise the outeru most coil of the hairspring and maintain the vraised portionin a plane parallel to the main body of the spring.

With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described andclaimed,

tion.

2 i it being understood that changes in the precise embodiment of the invention herein described may be made within the scope of what is claimed vwithout departing from the spirit of the invention. i

The invention is illustrated in the accompany ing drawing in which:

Fig. lis a top plan view;

Fig. 2 is a section on line 2-2 of Fig. 1;

Fig. 3 is a detailed View showing the last coil of the h'airspring in the position `just previous to making the bend;

Fig. 4 is a detailed view showing the last coil of the hairspring in the position just after making the bend; i

vFig. 5 is an enlarged view of the hairspring showing the raised overcoil.

,The tool is formed with a base l having mounted at one end a balance holder 2 secured by, screws to the base I and formed with a semicircular groove 5 to receive the balance 16 of a hairspring 1 having yan outermost coil 8.

A pair of supporting members 9 and I 0 are mounted on the base I. Member 9 is securely held to the base by screw 28 passing through a hole in said member, while member Ill is slightly movable through the screw 29 passing through a Slot in said member. These supporting members 9 and Ill respectively supporta pair of slides II and I2 which are also held by screws 28` and 29 passing through slots permitting longitudinal movement of the members l I and I2 on the supporting members 9 and IU. A handle member f3 controls the sliding action of the slides II and I2 through linksI It and I5 under manualoperakThe ends of thel supporting members 9 and Ill farthest from the link member I5 are formed with curved surfaces I5 and Il which receive the outermost coil of the hairspring `f3 and have mounted respectively 'thereon holding blocks I8 and I9 serving to hold the coil 8 in desired position.

The forward edges of the slide members Il and I2 are formed with tongues 20 and 2|, the under side of which is curved to t the surfaces I6 and I1 and the upper side is curved to Iit beneath the projecting edges 22 and 23 of the holding blocks I8 and `I9 respectively. The slide members I I and I2 are mounted for longitudinal sliding motion on the supporting members 9 and l0 by means of pins 24 in said supporting blocks passing through slots 25 in the sliding members while spring members 26 and 21 control the sliding motion ofthe two sliding mem- 3 bers II and I2 relative to each other through the adjustment of the spring tension by the screws 28 and 29 threaded into base I and passing through slots 28 and 29 respectively of the sliding members 9 and I0 and slots 28 and 29" respectively of the members I I and I2. These slots both in the members 9 and I0 and I I and I2 give a sufficient freedom of movement to the members to permit both a sliding movement in a longitudinal direction and a slight lateral movement. A spring 3 carried between members 9 and ID and housed within a groove 4 in memberA 9, normally holds said members in spaced relationship. A pair of pins 30 mounted in the supporting block I engage cams 3I and when forward movement of the slide member I2 engages the pins 2li and imparts further movement to the supporting member IIJ, said pins 30 cause a lateral motion of the supporting member I8 and its supporting slide I 2 to bring the supporting members together while they move longitudinally to thus produce a permanent bend in the top coil 8 of the spring held in bending position.

Threaded into the rear portion of the base is a limiting screw 32 having an elongated cylindrical portion 33 engaging a downwardly projecting pin 34 to limit the rearward motion of the supporting member IIJ. The pin 34 is aflixed to the supporting member I0 and projects downwardly into the opening 35 of the base I. A second limiting screw 36 threaded into the forward portion of the base engages a pin 3'! projecting downward from supporting member lil into the opening 38 of the base I. This screw 36 limits the forward motion of the member I2 yand regulates the distance which the outer coil of the hairspring is raised above the hairspring. In operation, a hairspring together with its accompanying balance is placed in the balance holder 2 with the spring drawn out and placed in a position shown in Fig. 2 so that the outer coil 8 passes below and is held beneath the overhanging end 22 of the block I8, the curved portion of the spring snugly fitting the curved surface of the ends I6 and Il. The end I 6 is formed with a curved cutaway portion 39 while the end ofy the opposing slide is curved at 49 to produce the desired curve in the hairspring overcoil. The curved surface 4I of the cam 3l is formed with extreme accuracy and guides the pins 39 so that the movement of the supporting member IIJ and its accompanying slide I2 produces just the exact curve necessary to make the overcoil.

The outer coil of the hairspring being fixed in a position shown in Fig. 2, the handle I3 is pushed forward, moving the slide member II into spring contacting position which is followed by movement of slide member I2 into a light spring contacting position. Continued movement of the lever causes the pin 24 to contact the end of the slot 25 and impart its sliding motion to the supporting member I0. Forward movement of the supporting member IIJ causes the. pins 30 to ride against the curved surface of the cams 3|'. moving the supporting member IB and its accompanying slide I2 laterally as it moves forwardly forcing the spring against the cut out portion 39 to produce the bends 42Y shown in Fig. 5.` The handle being released, the spring returns the slide to starting position and the coil is manually removed from the holding overhanging end 22 and allowed to return into the balance, the outer coil ofthe hairspring having a permanent vdeformation to produce a raised section above that of the main body of the spring.

With an instrument of this type it is possible to get uniformity in the raising of the overcoil. Heretofore, overcoils have been made entirely by hand and depended entirely on the skill of the operator. With this device it is possible for any one to raise a perfectly level overcoil and also to have uniformity in a great number of hairsprings.

What is claimed is:

l. A tool for raising an overcoil on watch hairsprings comprising a base, a balance wheel and hairspring support carried at one end of said base, a stationaryv slide supporting member, a movable slide supporting member adjacent to said stationary supporting member, a spring normally separating said members, each of said supporting members being narrowed at one end, said narrowed portions being curved on their top surface to receive the outermost coil of said hairspring, slides mounted for limited sliding movement on each of said supporting members, an adjustable spring to regulate the sliding contact pressure between each of said slides and its supporting member, a pin carried on each of said supporting members receivable in a slot in each of said slides to prevent lateral movement of the slides relative to said supporting members, a link connectingr said slides at one end, the other end of said slides being formed with tongue portions curved to fit the curved narrowed ends of the supporting members and to engage the outermost coil of said hairspring, a pair of blocks formed with an overhanging end mounted on the narrowed ends of the supporting members to coniine the outermost coil of the hairspringin desired position, a handle member connected to said link to move the slides upon movement of said handle, a pair of cam followers carried on the sliding supporting member, a pair of cams mounted on said base and engaging said cam followers to impart lateral movement to said sliding supporting member and its slide, whereby upon movement of said handle the slides move forward in order, dependent upon spring tension between the slides and their supporting members, within their limits, further movement of one of said slides moving its accompanying supporting member both longitudinally and laterally to bend said outermost coil of the hairspring to its desired shape.

2. A tool for raising an overcoil on watch hair'- springs, comprising a base, means for holding a hairspring and balance assembly mounted at on'e end of said base, a pair of sliding members mounted for manually controlled sliding movement carried on'said base, one oi said members moving longitudinally and the other of said members moving both longitudinally and laterally of said base; means for holding the outermost coil of said hairspring in predetermined position and in thepatn of said sliding members, means for selectively controlling the movement oi said sliding members to bring the longitudinal sliding member into clamping engagement with the outermost coil of the hairspring and to engage said clamped coil with said second sliding member to bend said coil into predetermined shape.

3. .A tool for raising the overcoil of a hairspring comprising a base, means carried by said base for supporting a hairspring and balance assembly means carried by said base and adjacent said supporting means engaging predetermined lengths of the edges of the outer coil of thehairspring adjacent the bending points, said means maintaining said outer coil in its original curvature, and means slidably mounted on said base for bending a portion of said outer coil into a plane parallel to and above the body of the hairspring While maintaining the original curvature of said outer coil.

4. A tool for raising an overeoil on Watch hairsprings comprising a base, means for supporting a hairspring and balance assembly, a pair of sliding members mounted on said base for manually controlled sliding movement, means located in the path of movement of said sliding members for cooperating with one of said sliding members to clamp the outermost coil of the hairspring in a 'predetermined position and means cooperating With the other of said sliding members to bend the outermost coil of the hairspring upon longitudinal and lateral motion of said second of said sliding members.

WILLIAM OGLE BENNETT, JR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTSi 10 Number Name Date 797,331 Stambaugh Aug. 15, 1905 1,251,765 Fonnesbeck et al. Jan. 1, 1918 1,844,309 Batz Feb. 9, 1932 2,341,428 Dorsey Feb. 8, 1944 

